An apparatus for directing the launch of a projectile from a canister includes a pusher plate disposed in the canister, the pusher plate having a sliding, sealing engagement with the canister to define a closed volume, the projectile being disposed in the canister and resting on the pusher plate; and means for generating exhaust gas into the closed volume to urge the pusher plate and the projectile toward an opening of the canister. The apparatus further includes means for directing exhaust gas to affect the trajectory of the projectile.